Superspec misfire and idle speed

[Guest MrToad]

I put carbs but most engines from single cylinder mowers to multi-cylinder giants use the vacuum from the intake to make adjustments to running criteria especially the ecu which will sense any leaks and adjust the mixture, if you have a turbo there will be more. Mine feeds to at least 6+ locations and I have had to put small fuel type clamps on each to ensure adequate sealing as the turbo deals out positive pressure as well as negative vacuum.

As Alan has a similar set up his knowledge will be invaluable.

[geordie40]

Well hopefully sorted it but it took a complete breakdown on way to local car show ( which I won 1st in class, photos to follow!!)

When it broke it wouldnt start or if it did it wouldnt idle at all and I eventually noticed I couldnt hear the fuel pump prime so wiggled some wires under bonnet and heard relays clicking, 30 mins later traced to a loose earth lead on the chassis (and it had been touching manifold so was a little melted), tightened up and started 1st turn.

Idle problem was down to accelerater cable not fitted into the throttle assy correctly.